Prior art techniques of broadcasting messages of information within a network of electronics elements, such as a computer system, typically involve electronics elements, such as semiconductor devices, that reside on a common bus, or “shared” bus. In shared bus architectures, information may be shared by each agent residing on the bus by placing the data on the bus and assigning an address to the information that all agents on the bus will recognize. In other shared bus systems, other techniques for broadcasting information may be used, but in most shared bus systems, data is broadcast to the various bus agents via the bus upon which all agents reside, either directly or through coupling logic.
FIG. 1 illustrates a prior art shared bus system, wherein broadcast data broadcast across the bus is shared with all other agents residing on the bus. In the example illustrated in FIG. 1, there are no intermediate bus agents through which the broadcast data must pass in order to be sent to not only the intermediate agent, but all agents connected to the intermediate agent, and so on.
FIG. 2, on the other hand, illustrates a typical computer system in which bus agents, including processors, are connected via a point-to-point interconnect. FIG. 2 illustrates a number of bus agents residing on a number of different buses. Typically, each agent may be a transmitter and a receiver of information by assigning a particular address to each agent to which data being sent across a bus corresponds. Because the bus agents illustrated in FIG. 2 do not all reside on a shared bus, however, broadcast data cannot simply be placed on the bus of the transmitting agent and detected by each agent within the system.